A quick tip on getting your walking foot on easily - move the needle down about 1/4 of an inch using the flywheel, then hold the walking foot so that your thumb is between the hook and the foot itself (the hook rests on your thumb). Put this over the needle bar first, then fit the shank and ta da, you're ready to go (assuming you've got the feed dogs up, something I neglected recently, and something that also results in tiny stitches)
If this is clear as mud, let me know and I'll take a photo of what I'm trying to describe